Laminated tubing



Aug. 14, i945. .1. N. TYNAN LAMINATED TUBING Filed oct. 13', 1942 :d lNvENToR J/-QMES TYN/V BlWw/M K ATTORNEYS Patented Aug. 14, 1945 LAMINATED TUBING V.lames N. Tynan, Chicopee, Mass., assignor to A. G. Spalding & Bros. Inc., Chicopee, Mass., a

corporation of lDelaware ApplicationOctober 13, 1942, Serial No. 461,9(l6 13 claims. (o1. 13siol This invention relates vto structural members, particularly tubular structural members of laminated construction. v

It is an object of the invention to provide an improved structural member of the above type which .isy particularly strong and which is adapted for many uses, for example, in airplane and glider construction, as control rods, as insulators, as o-il, air or water lines where rigidity and the withstanding of pressure .is a requisite, and as shafts for golf clubs and handles and shafts for divers other sporting implements. o

.It is another object of the invention to provide an. improved nonmetallic tubular structural memlber of laminated construction which may Ibe effectively used in place of metallic members, as

of steel, and `which may be used in places where because of special requirements metal would not be satisfactory.

Avfeature of the invention resides in the provision of a tubular member of laminated construction, including laminae of wood so arranged and disposed relative to each other that a vstructure having great strength per unit of weight is provided.

Another feature of the vinvention resides inthe provision of a tubular member of laminated construction, including superposed laminae of wood, which is particularly strong and which is so constructed that it has a high resistance against splintering, splitting and cracking.

Anotherv feature of the invention resides in the provision oi a tubular structural member of lamf inated construction including spiral wound strip material of woodand of composition liber and also including :at least vone lcored tubular unit of wood, all of the laminae being adhesively secured together and the several laminae being so formed and so related to each other that a particularly novel and advantageous structure is provided.

Another feature of the invention resides in the provision of the method for making the structural member embodying the subject matter of the Aabove invention. A

Other objects, features and advantages will hereinafter appear.

In the drawing:

Figure 1 is a side View of Ia portion of a tubular member embodying the present invention, oertain of the elements being lbroken'away for clarity of illustration, and` showing the manner in which the member is built up on a mandrel.

Fig. 2 is an enlarged sectional view taken on Fig.- 3 is a.' perspective view showing a portion of a composition'fiber strip used in the construction. I

Fig. 4 is a perspective view 4showing the half tubular sections' used in the construction; l

Fig. 5 is a perspective view, showing a portion of a wood strip used in the construction. v Fig. 6 is a view similar to Fig. 1, but showing a modification ofthe present invention.

Fig. 7 isa sectional View, similar tol Fig. 2; but tak-en on the line 1 1 of Fig. 6.

Fig. 8 is a fragmentary View, showing a modined mandrel Y Before describing the present improvements and mode of operation thereof in detail it should be understood that the invention is not limited to the details of construction andarrangement of parts shown in the accompanying drawing, which is merelyy illustrative ofthe present preferred ernbodimentls, since the invention is c'apable of other embodiments, and the phraseologyemployed is for the purpose of description and not of limita# tion.

Referring more particularly to the drawing and firstv to Figs. 1-5', there is shown for the' purpose of illustrating the present invention "af tubular structural member Il built up of 'a plurality"oic laminae, and including an inner layer made'up of a composition fiber strip |12 `spirally wound with the longitudinal edges thereof in abutting rela'- tion.

' A composition fiber strip made from? processed highly compressed iibrous stock land sold as Continentalber by the Continental Diamondlibre Companyof Newark, Delaware,` has been used with success in the construction of the'struc-tural member embodying the present invention; This Continental fiber is an uncalendered vulcanized.) fiber using a cotton raggbase vulcanizedl through the medium of Zinc ch1oride. However, it will be readily appreciated lthat other composition vijlber strips may likewise b'e utilized,which are tough,

moved.

which do not adversely splinter, and which advantageously and preferably have a hard smooth abrasion resisting surface but 'with affinity 'for the adhesive used fin bonding the ber layer 4to adjacent layers inthe structural member l l`.` Overlying and adhesively secured'tothe spirally wound fiber stripI Il is a tubular unit I3 advan# tageously comprising a pair of half tubular 'sec' tions I4 and l5 of wood. l'Of importance, and as shown best in Fig. 4, the sections 'preferably and advantageously are so cut that they includecontinuous long grains i6 the full length of the tubing.` Thus, in practice these sections I4 and I 5 have been Imade from` straight grain wood stock and the continuous long grain is included in the resulting unit I3 in the same manner as though a straight grained rod were bored concentrically to produce a solid wooden tube. A much more accurate formation and disposition of the bore of the resulting unit, however, is possible in the forming of the unit from the sections I4 and I5 than by forming the same by .concentrically boring a solid wooden tube. Wall thickness of about l" for the half tubular sections has been used, but this may vary depending upon strength and other characteristics desired.

Spirally wound on the tubular unit is relatively thin strip material of wood, which as shown advantageously includes a plurality of superposed strips I'I, I8 and I9, wound with adjacent superposed strips being wound in opposite directions and adhesively secured to each other, and with the innermost strip II adhesively bonded to the tubular unit I3 and wound in a direction opposite to that of the inner fiber strip I2.

Oi' importance the wooden strips, are preferably and advantageously not made from veneer of the conventional rotary cut or sliced variety which has no through continuity of grain, but are made from straight grain planks of prime stock and are cut from the edge at all times so that they are in effect individual boards which, as shown best in Fig. 5, provides a straightl strip possessing all of the long grains along its full length and extending continuously through the thickness thereof. Such a strip, it will be appreciated, is not a conventional veneer, and it embodies maximum tensile strength and bending ability. The wood used may be ash, hickory or. any other suitable wood, advantageously of a fibrous character.

To complete the structural member, there is a second or outer strip 2I of composition fiber, similar to the inner strip I7., adhesively bonded to the outermost Wooden strip I9 and spirally wound thereon in the opposite direction.

The resulting construction, for reasons which will be more fully set forth hereinafter is particularly strong and resistant to splintering, splitting andv cracking.

In building up the structural member I I, above described, and as shown best in Fig. l, there first is wound on a mandrel 22 of the size required for the inside diameter of the completed member I I, a composition liber strip I2 which may be approximately 1%;4" thick and 1" wide, but also may be of other thickness and/or width depending upon the requirements of the particular construction and upon the diameter ofthe mandrel, as will be readily appreciated. As shown, this inner strip is spirally wound in edge abutting relation. The pitch of the spiral, as shown, has

equal to that of the mandrel plus the ber winding. Advantageously, these two sections also are coated with a suitable and preferred adhesive such as above explained, and clamped tightly in position with the wall comprising the bore of the unit, contacting the spirally wound fiber strip, and with edge walls of the sections in butting relation. Any suitable form of clamping means may be utilized, and the sections are preferably retained positively and tightly clamped relative to each other until the adhesive between the sections and between the sections and the fiber strip, has thoroughly set or dried.

After removing the clamping means from the half tubular sections, a first wooden strip I1 is spirally wound around the sections as shown in Fig. l, with the strip preferably and advantageously wound in a direction opposite to that of the inner fiber strip I2. A suitable adhesive, such as explained above, is applied to the outer surface of the half sections I4 and I5 making up the tubular unit I3, and preferably also to the inside face of and to the longitudinal edges of the wooden strip. The application of the adhesive, it will be understood, may be accomplished either prior to or concurrently with the winding on the first wooden strip.

Preferably, and as shown, additional wooden strips I8 and I9 are applied in the same manner as the first wooden strip I'I, with the adhesive being applied either prior to or concurrently with the winding operation. Advantageously and as shown, each of the additional strips is wound in a direction opposite to that of the underlying strip. The thickness and width of the wooden strip material may vary depending upon the size of the tubular member being made and/or upon the particular physical properties desired. For

example, the strip material may have a thickbeen found satisfactory, but it is to be understood that the pitch used may be determined by the particular size of the lmandrel and/or the size of the completed tubular member.

A coating of adhesive is applied to the outer face of the fiber strip, preferably after winding ness of sla and a width of 1, or it may have a thickness of 11g" and a width of 2", or some other width and thickness depending upon the requirements of the manufacture.

After the last wooden strip I9 has been wound in position, a final or outer composition fiber strip 2 I, like the inner strip, is spirally wound thereon, advantageously in an opposite direction as shown, and with adhesive applied to the inner face and, if desired, to the longitudinal edges thereof prior to or during the-winding operation.

The winding of the several fiber and wooden strips may be accomplished through the use of any suitable and conventional means for winding strip material, either by the revolving of the mandrel. or by utilizing an apparatus and method involving. the rotating of the strips around a stationary mandrel.

Advantageously the winding is done under tension and this tension normally will serve to produce the necessary clamping effect. However, if desired a suitable clamping means, such as a tubular clamp, may be applied over the completed structural member until the adhesive has fully set. Completing the steps in the making of the l structural member, the mandrel 22 is removed from the center thereof. l

In a structural member II, .constructed in the manner above set forth, the inner iiber strip I2, securely bonded to tubular unit I3, serves to prevent and/or very effectively resistsplintering'or splitting of the wood thereof in impact or shock strains,v and, in addition, provides a smooth and true inner bore for the structural member. 'I'he half sections making up the tubular unit I3, being formed from straight grain stock providing con- 'unuousuorrgfgramane auuuengthitnemdfmmvide "s'trength-and-'dispose fgrain running longitudinally 'running longitudinally 'and through the ftliiki -ness "thereof, which `are'wound yfin `lreverse Adirections, provide fa ldiagonal 4forissJcross'ing fof ythe grains in `the Vseveral 'wood strips vand the longitudinal grain of '-thevunderlying fhlf i tubular sec- "ti'ons, and -serve `not y'only to prevent ithe `long 'grains I of `the haii r'sections j'from splitting, tearling and ysplintering, "but Lalso to i:strengthen leach 'other due ito the varying directioni their iWrap and o'f Lthe grain.

The outer'liiberlstrip'fll-adds appreciablsr tothe tensile strength 1o'f the outer IWood "Wrapping, 'agfain preventing splitting, splintering and tearing, l'and f moreover, provides'the xiished structural Imember lwith a hard, smooth-abrasion -resisting lsurface Vwhichtilt lthe same Vtime has fan 'affinity ffor the adhesive eused 'so Aithat it will 'perv-mit the readyvand'fefectivebonding Iof the memz/ber inside a member of :larger diameter ortolany surface o-f the same radius.

If desiredand as shown Ain Figs. 46 and '7, a l'structural member YI I fc'f modified construction embodying the principles fof vfthe :present "invention may be employed. rThis modiedconstru'ction, which is particularly applicable 'to -tublar fmemberso'f larger diameter, is a'essentially ithe same as'the4 construction 'of xthe-member II Y'shown' in Figs. "1 'and 12,diiering therefrom in the rincorporation `of at least 'one `additional Lpair of tubular half sections 2-3 'and 24 of construction like 'l the half sections vI"4 land YI 5, disposed `-intermediate'anf underlying sectionniadeup'of-"spirally `wound wooden strip rmaterial which, 'as f-shown, 4vincluclesstrips 1'1, l'I8 -and I9 'thesame "as the `Wooden strips 'embodied in the 'construction of Fig. f8, itc lpermit iremoval'from'ieither jend of lthe ltubing.

"While theinner vand 'outer iiberl tubes, las y:above fdescribed, preferably -are liformed* of =spirally Lwound strips, stheymay'falsoloe formed of ipre- `formed =tubing #of ther same composition*asthe iiberzstrips. 4The:illustrationorthiscconstruction 1in `cross-section is :exactly 'th'esame :as the. showing `oftire itubes #using spirally Zwound Tiiberlsin'ips pictured in Figs. 2 and 7. 'Ifhe manner-difformiing the fcompiete ltubular members fusing prefformed ibeftubes would be 'the 'samefas Ithatof the ftlibiilar members rs't described Lexcept that the preformed loer 1tubes'IWoul'd be :slipped'in'to position A-instead f df :'spirally-Wrapped in position. Variation-s yand fmodications' may A'be mad'e VWithin"the scope o'f'ithis Einvention vfand portions ridf'the'improvements maybe used without others.

fHaving "thus described fclaimed fasfnewiis '1. fifiA 'tubular- :structural tmerberfcomprising 1an `inner spirally 'woundiber strip; -'a woodenftubu- -1ar unit fon fand Tadhesively 41secured 5to Lsaid? spirally wound berustrip; a plurality -rof isuperposed strips fo'f wood :having '.'longitudinally extending f-,graim` lspirally 'Wound :on fsa-id tubular r` -unit i and 1adhesively'` securedito the latter andtofeachother; (and La spirally Wound :Tiber strip von and adhesively `secured fto v`the 'outermost of saidjsuper- 2. .fA tubular structural' yfmemberj'including a vspirallywound fiber strip; fa wooden tubularlunit on 'airdadhes'ively-'securedto said'ber strip, .fsaid 'tubular lunit ihaving continuous 'lon'g v'grain fex- ).35 'tending longitudinally thereof; -spirallyv Wound Wooden 'strip material 'on :and adhesively secured f-to said tubular unit v'1in edge-'abutting 'relation; and a spirally 'wound ber strip onand ,adhesively Isecured to said -spirally Wound wooden Figs. l'and 2, andanoverlyingsecti'on of `-spirally- 40 VVstrip material. l

wound wooden stip'material which, as Vshown, vmay includeonestip '-25'exactlythe same as the 4strips I1, 'I8 and `If9. As'in'thefconstruction'of Figs. 1 and 2,an outer 'strip "tl "o'f 'composition 'ber isispirally wound-`to provide'thefoutersur- "face 'of' the jstruturalmember and `is'adl're'svely llo'ondedto the 'underlyinggportion df 'the structural member.

It will be readilyfappreciatedthatftheapplication'of thefa'dditionallhafsections.'and 2'4 and of the additional wooden"strip25"may^be "accomplished vin 'a manner 'similar "to the 4previously applied "half sections `I4 and f5 'and 'strips "I1, IB and I9, withall dfthe laminaema'kingupithe completed lmember "being adhesively l"bonded `together. .Also,it .wi1l`bef'appreciated'thatthe number f layers of'wooden-strips both ,overlying and underlying the Aouter pair ofhalfsectionsmay "be varied i with .respect .to "the number 'illustrated' in the drawings, 'and'that under certain conditions the outer Wooden strip 25 may be omitted.

Of special importance, however, it is to be noted, as shown best in Fig. 7, that the joints between the outer pair of half tubular sections 23 and 24 are offset circumferentially with respect to those between the inner pair of half sections I4 and I5, so as preferably to be located midway therebetween. e

Where tubular members of a curved shape of any desired radius are required, the procedure as described above in connection with Figs. 1-7 may be followed except that pre-curved half tubular sections may be used and except that a mandrel 22' is preformed to the desired curve and may be made up to separate in the middle as shown in f3. itubular structurallmemben 'includingyan inner -spirally wound composition 'fiber stripj fa cored tubular -unit of =wood jon jand adhesively secured to said'fber s'tri'pgsa'id'c'ored tubular-unit 14&5 being formed to provide -'continuous 4long. 4grain extendingiongitudinally fthereof; a plurality of strips o'f Wood frespectively'i sprally Wound infop- :positel directionsand inedge vabutting relation,` on vsaid 'tubular unit, the inner lone o'f 'said :wood

v50 Ystrips fbeing adhesively l'secured vto said tubular unit, and adjacent ofsaid' superposed strips 'being fadhesively secured i tofeach other, said super- 'p'osed Wood stripsbeingformed with the'grain -runningllongitudinallyitirered andextendingrcontinuously through the thickness thereof; ande-an outer composition y'ibe1-s`1,1"ip spirally 'wound on and adhesively,securedrelaltive to said underlyingplurality'f spirally-wound wood'strips.

4. A tubular structural member 'including an 1730 `inner rspirally'wound `composition `*fiber strip; a

rst cored tubular "unit lof "'Woodon lsaid, 'ber strip; spirally Wound wood strip material on said tubular unit in edge-abutting relation; a second cored tubular unit of wood on said Wood strip material; and an outer spirally Wound composition fiber strip on said second tubular unit, all of said superposed elements being adhesivelysecured relative to each other.

5. A tubular structural member comprising radially spaced inner and outer spirally Wound ber strips having the characteristics of toughness and freedom from splintering and having a hard smooth abrasion resisting surface; and an intermediate structure adhesively bonded to said fiber strips, including a tubular unit of wood divided circumferentially'into a plurality-oftransversely related sections extending longitudinally of the structural membenland spirally disposed strip material of Wood on andadhesively bonded f grain .extending longitudinally of the Ystrip with to the tubular unit, said strip material of Wood f5 being in edge-abutting relation andhaving continuous long grain extending longitudinallyand through the thicknessl thereof `to he disposed spirally of said tubular unit and said structural member. l 6. A laminated tubular structural member comprising radially spaced inner and outer layers of spirally disposed strip materialhaving the` characteristics of toughness and freedom from splintering and having a hard smooth `abrasion resisting surface; and an intermediate structure adhesively bonded `to said inner and outer-layers, including a tubular yunit made up of a plurality of longitudinally disposed andcircumfe'rentially related segmental sections of wood,l said sections, having continuous `long main grain running longitudinally` thereof `and extending in generally parallel relation through the thickness of the sections in the manner of straight-grain Wood stock,

and spirally disposed strip material of Wood on and ,-25

adhesively bonded to .said tubular unit, said strip material of wood being in edge-abutting relation and having the grain extending longitudinally and through the thickness thereof tobe disposed spirally of the grain of said tubularunit.A n,

l'7. yA laminated tubular member comprising inner and outer layers of fiber 'strip material; and an intermediate structure Vadhesively bonded thereto, including a first tubularunit'of straight grain Wood with the grain running longitudinally;. thereof, first spirally wound strip material of wood on said first tubular unit, :a second tubular unit of straight grain Wood Withthe grain running longitudinally thereof, on said rst strip material of wood, and second spirally Wound strip-material..y on said second tubular unit, said first and second spirally Wound strip material'of wood having long edge grain running longitudinally thereof and spirally disposed relative to the grain of said first and second tubular units.

8. A plywood structure comprising an inner and outer spiral layer of edge grain `wood having the grain extending longitudinally of the strip with they spirals in edge-abutting relation; and an intermediate section comprising at least one tubu-A lar unit made up of a plurality of longitudinally disposed and circumferentially related segmental sections of Wood, said sections having continuous long main grain..running longitudinally .thereof the spirals :in ,edge-abutting. relation; and an intermediate section comprising a plurality of tubular4 units, .eachimade up of a plurality oflongitudinally disposed ,f and -I circumferentially related seg-mental sectionsotwood,` With'the-joints of the sections finonesunit offset :with respect to -the joints in the other.- unit, said sections having continuous .long mainpgrain` running longitudinally .thereof z and vextending .inA generally parallel rela- .tion through the thickness of :the sections in the mannerof straight, grain .'stock, -thelinner and .outer `layers and intermediate layenbeing adhesively bonded together into a rigid structure. "10.5 Avtulmlarl structure.; includingfy a..tubular wooden core havingM'the grain extending flongivtudinally thereof ;\v anda yspirallyl 4Wound strip of Wood having; the .turns-.thereof in edge-abutting relation andfadhesively .bondedwtogetherg and to the ycore, said` stripA of ywood.havingtcontinuous edge; vgrain therein, extending., throughout the thickness thereofand `longitudinally thereof and disposed in spiralrelation tofthe grain of the tubularcore. Y, i

:LLAAI tubular structure including a tubular wooden ,core--havinggv the -grain extending :longitudinally thereof,` said core comprisingaplurality .of longitudinally.A extending,7 sections adhesively -securedVVV together; andraV spirally wound strip of wood having .the turns; thereof .in edge-abutting Vvrelation andhadhesivelkbonded together land to `.the core, said strip of wood having continuous edge grainl thereiny extending through the. thickness vthereof and longitudinally thereof. and disposed in spiralrelation to thegrain `of v.the tubular core. l

,12, A. tubular structuredncluding Aa v.tubular lwooden core havingA the lgrain extending longitudinally thereof, said. core comprisinga plurality vof pairs of half ,tubular Wood sections,v said pairs of sections being sodisposed relative` to each other thatthe joints betvveen onepair are circumferentilally offset relative tothe joints between another Ipair; .and a-spirallywound strip of Wood having the turns thereof ,inv-.edgefabutting relation and adhesively bondedtogetherand to thelcore.. said .stri-p of Wood having .continuousedge graintherein-extending throughthethickness. thereof and longitudinally thereof and disposed in spiral relation `to .the grain of the tubular core.,

, i3. A tubular` =structurejinciuding a tubular Wooden .core .having `the .grain extending longitudinally thereof; and.spirally pound vstripsof wood having theturns thereof in edge-abutting.'1ela tion and adhesively4 bonded 'together and tothe and extending inv-generally `parallel relation(55 core, saidstrips ofwood being wound intoppo'site directions and each having continuous .edge grain therein extending ,through-the thickness thereof and longitudinally 'ythereoffanddisposed. in spiral relation tothe grainvofv the tubular core.

' .',JAMES N. TYNAN. 

